1. Field of the Invention
The present invention is directed to a method, an apparatus and a system for the condensation of gases/fumes/vapors and particularly an apparatus for condensation of fumes during filling and storage of liquid fluids.
During storage and filling of fluids in tanks or vessels there is a problem that fumes or gases escapes from the handled or stored liquid. This is particularly prominent with volatile liquids and cooled, liquid gases. These gases or fumes have traditionally been allowed to escape into the atmosphere. This has lead to loss of fluid, pollution, and poor working conditions for people in the area. Examples of such liquids are crude oil, liquid natural gas (LNG) and other hydrocarbons.
Volatile liquids begin to produce fumes or gases during storage, and this creates a pressure build up in a tank where the liquid is stored. This pressure must be vented or bled off if it exceeds a certain value in order to avoid excessive loads on the tank where the liquid is stored.
Liquid will displace the gases or fumes contained in a tank during filling, and these gases must be vented or bled off to prevent pressure build up in the tank.
2. Description of Related Art
Various solutions to these problems have been previously suggested, and the solutions have comprised various complicated suction and condensation devices. Similar devices have particularly been used in connection with storage and transport of liquid gases. Examples are shown in the publications described below.
Norwegian Patent No. 305525 shows a “Method and gas Apparatus for Transport and Storage of Liquidized Natural Gas” Boil off is taken from a tank, and condensed in a condensation device with a cooler, and is led back into the tank. The device separates methane and nitrogen, and the nitrogen is vented into the atmosphere.
U.S. Pat. No. 2,784,560, shows a “Process and Apparatus for storage and shipping of Liquefied Gases” Boil off from the liquid gas is circulated in a device with a cooler, and is cooled by means of another liquid gas, to condensate the boil off and lead this back into the bottom of the tank.
U.S. Pat. No. 3,733,838 shows a “System for Reliquefying Boil Off Vapor from Liquefied Gas”. The system comprises an insulated storage tank, a venturi, a pump, and a heat exchanger. The system is intended to be used in connection with storage of liquid gas. A part of the liquid gas is compressed, and is expanded in a heat exchanger to provide cooling. The storage tank is cooled by expansion of a partly condensed stream that is led into the part of the tank, containing vapor.
U.S. Pat. No. 3,921,412 shows a “Vapor Recovery Apparatus Employing a Dispensing Nozzle with Condensing Capacity”. The nozzle is placed in a filler opening, and cools vapor/gas flowing out during filling, to condense the vapor, and let it drip back into the tank.
With the exception of this, the publications concern quite comprehensive systems for storage of cooled liquefied gas. None of these publications seeks to solve problems relating to shipping and storage of volatile liquids on a larger scale. In addition, various suction devices are known that suck the vapor/gas from a tank to be filled, condense the vapor/gas, and leads the condensate back to the tank the liquid comes from.